BANGOR, Maine — Five months after the company was sold to a Milwaukee conglomerate, Telford Group Inc., a Bangor-based aviation maintenance firm, is expected to lay off roughly half of its 65 employees.

Telford General Manager Bob Ziegelaar said the decision is part of changes by the new parent company, ACC Holdings LLC, which took over last September.

“They were unsure how they were going to incorporate this facility, so the status quo remained for awhile,” Ziegelaar said Wednesday. “But they came to the conclusion that significant changes would need to be made.”

All employees have been notified about the layoffs, which will go into effect within the next three to six months.

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“In most cases, employees will have at least 60 days’ notice,” he said. “They are taking it pretty well, considering. There have been plenty of rumors going around for awhile so at least now they know what they are facing.”

After the sale last September, a spokesman for ACC, which stands for Air Cargo Carriers, acknowledged that there would likely be consolidation.

Ziegelaar said Wednesday that the parent company also has authorized him to explore selling the Telford Group’s operations in Bangor to another company, but that hasn’t happened yet.

“The commercial side of aviation management has been tough in this economy, and [ACC] doesn’t have experience in the maintenance aspects that we do here,” he said. “I’m fairly optimistic that another company will emerge.”

In addition to its Bangor facility, the Telford Group has a research and development facility at the former Loring Air Force Base in Limestone that employs approximately 20 people. It also has locations in Alabama, Texas and Maryland that are now part of ACC.

Telford Allen II founded the Telford Group in 1982 in Waterville as a mom-and-pop charter flight company. It then relocated to Bangor in the 1990s and evolved into a regional and national leader in airplane parts sales and maintenance.

Allen has not been involved in operations for several years, but his two sons, Telford Allen III and Travis Allen, held management positions with the company until last year, when the family decided to sell its interest to ACC. Terms of the private sale were not disclosed.

ACC Holdings specializes in scheduled air cargo operations, aircraft integration, overhaul and parts sales, according to information provided by Telford. The company operates cargo services for UPS and DHL and is the largest civilian operator of Shorts aircraft in the world, according to its Web site.